BOLL MATURITY DATES FOR LATE SEASON COTTON FLOWERS

Decisions pertaining to crop termination and late season pesticide applications are best made with some understanding of the maturity status of late season cotton bolls. Research conducted by Silvertooth et al. (1996) has shown that the standard Arizona cotton heat unit (HU) system (Brown, 1989) can be used to predict boll maturity (hard, green boll; fiber elongation completed) and boll opening. This work indicates 600 HUs are required after flowering for a boll to reach physiological maturity, and an additional 400 HUs are required for the mature boll to open (1000 HUs after flowing).